Accessing a Synology NAS without a router

Recently, I had an issue with my home router, but I needed to access some files on my Synology NAS. Below is a quick self-reminder of the method I used to connect to the web interface. This should work for any type of network device.

1. Plug the NAS into your computer via Ethernet.

2. Since the NAS lost its connection to the router, it will have assigned itself a fallback IP from the link-local range. Using arp-scan, we will scan the entire IP range to find the NAS:

   sudo arp-scan --interface=[your-interface] 169.254.0.0/16
   

   For example, the IP might be: 169.254.239.105.

3. Once you have the IP, set your PC's IP on the same interface to be in the same range, for example 169.254.239.50:

   sudo ip addr add 169.254.239.50/16 dev [your-interface]
   

4. You should now be able to access the Synology web interface on 169.254.239.105:5000 🙂